\[
\boxed{
 \left( {\frac {\rm d}{{\rm d}x}}y \left( x \right)  \right) ^{4}+3\, \left( x-1 \right)  \left( {\frac {\rm d}{{\rm d}x}}y \left( x \right)  \right) ^{2}-3\, \left( 2\,y \left( x \right) -1 \right) {\frac {\rm d}{{\rm d}x}}y \left( x \right) +3\,x=0}
\]